Despite a growing interest in the use of self-report measures of narcissism among student, community, and clinical samples, the research on narcissism in prison samples is sparse, despite elevated rates of narcissism in these samples. The current study examined the relations between commonly used measures of grandiose narcissism (Narcissistic Personality Inventory–13 [NPI-13]), vulnerable narcissism (Hypersensitive Narcissism Scale [HSNS]), and narcissistic personality disorder (NPD; Personality Diagnostic Questionnaire [PDQ]) in a sample of adult male offenders (N = 179). The NPI-13 and PDQ NPD scales overlapped substantially with one another and manifested similar empirical profiles (rICC = .81), with both being substantially correlated with interview-based symptoms of NPD, entitlement, psychopathy, and externalizing behaviors. Conversely, the HSNS manifested more limited relations with other measures of NPD and related traits (e.g., entitlement), as well as externalizing behaviors, and was more strongly related to internalizing symptoms. Consistent with previous work, NPD appears to be a blend of grandiose and vulnerable narcissism as the PDQ’s empirical profile overlapped with that of the HSNS (rICC = .51), which was not true for the NPI-13 (rICC = .18). Analyses of the incremental validity of the 3 measures suggested that the NPI-13 was particularly successful in accounting for unique variance in these relevant criteria. These results underscore the benefit of utilizing multiple measures to distinguish empirical correlates of grandiose narcissism, vulnerable narcissism, and NPD.